A variety of sheet article processing apparatuses and methods exist in the art for processing sheet articles such as, for example, mail media comprising paper envelope inserts which are processed at high speeds. To insert such sheet articles into envelopes, the sheet articles, folded or unfolded are usually collected in a stack and conveyed in a conveying path to an envelope inserting machine which has a continuously moving transport chain with discrete time windows inside of which a successful delivery of a stack of sheet articles is possible. A stager mechanism is therefore necessary between the collector and the envelope inserting machine to correctly correlate proper delivery of the sheet articles to the envelope inserting machine within an appropriate time window thereof, and various types of stager apparatuses exist within the art of sheet processing as is apparent to those of skill in the art.
As is readily apparent to those of skill in the art of sheet processing, a need commonly exists for selectively diverting sheet articles from the conveying path during collection thereof subsequent to folding and prior to advancement of collected sheet articles to the envelope inserting machine so that the diverted sheet articles can be manually processed. In the past, sheet articles have been diverted from the conveying path by using a solenoid-driven ramp or gate to selectively divert sheet articles above or below the conveying path. This divert method requires two electronically controlled mechanisms which are the divert solenoid and the mechanism for transporting the sheet articles in the conveying path. This prior art method of diverting sheet articles can therefore be said to be "in-line" with the conveying path of the high-speed media processing apparatus. It is a requirement of this prior art method therefore that an additional component, i.e. a solenoid, be utilized and that the machine processing the media be long enough to accommodate the divert gate. The use of the divert gate also has the potential of slowing down the overall system performance due to the activation time required to open and close the gate.
For the actual conveying or transporting of sheet articles, it has in the past been common for high-speed media processing apparatuses to utilize a belt with one or more lugs or push members attached thereto for causing the sheet articles to be conveyed along a predetermined path. One apparatus used in the past utilizes a timing belt constructed of neoprene with screw-on lugs attached thereto to push or transport folded sheets of paper during high-speed media processing. An electro-magnetic clutch/brake combination is used to control the motion of the timing belt. As known to those of skill in the art of high-speed media processing, the motion of such a timing belt is typically slow, the timing belt breaks very frequently with continued use, and the clutch/brake system ultimately wears out. Such a timing belt is also usually very difficult to replace since it is a closed loop and typically requires some disassembly of the machine for replacement.
Another method used in the past for transporting collected sheet articles collects sheet articles over a moving belt, thus energizing a solenoid that moves a bracket stopping advancement of the sheet articles and simultaneously pushes a roller down on top of the sheet articles to advance the sheet articles past the bracket. This method has proven somewhat unreliable for advancing larger stacks of sheet articles, particularly at higher speeds, because of the tendency for the sheet articles to delaminate upon acceleration.
Additionally, metal chains with steel push pins or lugs have been used in media transport applications, but due to their inherent weight and the weight of the gears or sprockets used to drive them, they severely limit the speed at which media can be processed and reduce the ability to precisely control the motion of the media.
In light of the prior art apparatuses and methods for conveying and diverting media such as sheet articles in high-speed media processing, room for improvement exists in the art of sheet article processing for a document collector, diverter and stager apparatus and method for collecting sheet articles before or after they have been folded, selectively diverting the collected sheet articles from the conveying path or advancing the sheet articles to a stager, and selectively further advancing the sheet articles from the stager at a predetermined time to another location such as, for example, an envelope inserting machine.